I wrote an intricate reply then my phone died. So, you should read Three Waves of Modernity and peruse Nietzsche and Modern Times by Laurence Lampert. In short, science is not the category but the branch. In other words, the scientific method is a particular type of philosophy but it is not an exhaustive definition of the later. Philosophy, on the political level at least, fundamentally deals in Noble Lies. Moderns chose to alter the application of such but that doesn’t mean that all modern philosophy is scientific. Rousseau and Nietzsche, in particular, certainly are not.